Effect of therapeutic dose X rays on mechanical and chemical properties of esthetic dental materials

• Main Authors: Adriana Dibo da Cruz, Mário Alexandre Coelho Sinhoreti, Gláucia Maria Ambrosano, Alessandra Nara de Souza Rastelli, Vanderlei Salvador Bagnato, Frab Norberto Bóscolo
• Format: Article
• Language: English
• Published: Associação Brasileira de Metalurgia e Materiais (ABM); Associação Brasileira de Cerâmica (ABC); Associação Brasileira de Polímeros (ABPol) 2008-09-01
• Series: Materials Research
• Subjects: ionizing radiation; radiotherapy; spectroscopy; Fourier transform infrared; dental materials
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392008000300014

The aim of this study was to investigate the influence of therapeutic dose X rays on the microhardness (MH) and degree of conversion (DC) of two different esthetic restorative dental materials. The materials were photo-activated with a LED light-curing unit using three cure-times: 5, 20 and 40 seconds. The photo-activation was carried out in two distinct periods: before and after irradiation with doses of 5, 35 and 70 Gy, from a 6 MV X rays beam. In accordance with the methodology used, it was conclude that a therapeutic dose does not have a detrimental effect on the photoinitiator molecules, because the photo-activation occurred after they were irradiated. When the irradiation was applied before photo-activation, the materials showed MH improvement, but when photo-activation was performed after irradiation, there was less improvement. However, there was no correlation between MH and DC. Thus, a therapeutic dose applied to cured material can promote linking and breaking of chain bonds in a non-linear way.